1. I have heard some negative comments concerning the D2's SQ being overly "cold" with harsh treble. This concerns me as I do prefer a warm sound even though I have grown to like the Zune's ultra clean signature.
Please share your opinion of the D2's sound signature as it pertains to warm vs cold.

2. The vertical album art flash skin seems very cool (I love album art). Can you configure it so the HP out is at the bottom (where it belongs, IMO)? Also - how does using this effect the battery life?

Edit: 3rd question: Does the D2 have DJ settings that allow you to play, for example, just unheard tracks?

1. SQ is something I'm not really comfortable talking about since it's so subjective, but I think the claims of it being "cold" are overcritical. It is very detailed though, and certainly not to everyone's taste, but I happen to like it. But you'll want to get some more opinions on this.

2. In the thread on iAudiophile (completed flash skins), the preview image of the vertical skin shows two pictures of the theme, one with the HP out at the top and one on the bottom. So, I assume the answer to your question is yes. I'll see if I can test this out for you though. Flash skins result in less battery life. I can't tell you how much, as I don't use them for this reason.

3. I'm not sure I understand this one. It's nothing I've encountered on the player, and it sounds like a nice feature, so I'm going to say no.

I'm not sure if you're aware, but you should know about the file limitations before you purchase the D2, I think it's 6,000 files now; 3,000 on internal and 3,000 on external.

I hope this helped, and I'll go confirm the Flash skin now.
Edit: As it stands, it only displays with HP out on top. This doesn't make much sense to me, as right-handed control would be easier with the buttons on the other side. But the source is available, and shouldn't require much editing to turn around. Or there are other large album art skins available.

1.) The sound quality highly depends on the phones you pair with the D2 (or any other player, for that matter). My D2 sounds warm and laid-back with the Atrios, but cold-ish and analytical with the q-Jays... headphones and quality of your audio files are a very important part in this equation. The D2 sounds alright (or "excellent", depending what player you come from), nothing to complain about, IMO. It sounds even better with higher impedance phones or a headphone amp (like 99% of all other players out there).

2.) If you get hold of the source Flash file, you can do almost anything to a theme. Battery life on newer firmwares seems to be worse than on older ones in general. Flash support might or might not have anything to do with that.